\makeatletter
% \providecommand{\leqnomode}{}
% \renewcommand{\leqnomode}{\tagsleft@true\let\veqno\@@leqno}
% \providecommand{\reqnomode}{}
% \renewcommand{\reqnomode}{\tagsleft@false\let\veqno\@@eqno}

% Clear even-numbered pages
\renewcommand{\cleardoublepage}{\relax \clearpage
    \if@twoside \ifodd\c@page\relax
        \else \thispagestyle{empty} \ \clearpage\fi\fi}

% For two-sided documents
\renewcommand\ps@headings{%
    \let\@oddfoot\@empty\let\@evenfoot\@empty
    \def\@evenhead{\sffamily\thepage\hfil\slshape\leftmark}%
    \def\@oddhead{\sffamily{\slshape\rightmark}\hfil\thepage}%
    \let\@mkboth\markboth
    \def\sectionmark##1{%
        \markboth {{%
                    \ifnum \c@secnumdepth >\z@
                        \thesection\quad
                    \fi
                    ##1}}{}}%
    \def\mySubSectmark##1{%
        \markright {%
            \ifnum \c@secnumdepth >\@ne
                \thesubsection\quad
            \fi
            ##1}}}

\renewcommand\ps@plain{
    \let\@oddhead\@empty
    \def\@oddfoot{\hfil\sffamily\thepage\hfil}%
    \let\@evenhead\@empty
    \let\@evenfoot\@oddfoot}

\makeatother
